The present invention relates to automated cleaning systems and more particularly to such a cleaning system for conveyors and conveyor belts such as those used in food processing plants.
Meat processing and other food packaging plants have a multitude of conveyor systems that must be cleaned at least nightly in accordance with government regulations. In the past, workers have brought carts onto the plant floor with long hoses to clean the conveyors manually. The process consisted of 1) rinsing the conveyors with high pressure hot water (xcx9c140xc2x0 F. @ 250 psi); 2) covering the conveyor with an industrial strength soap solution; 3) repeating the high pressure hot water rinse to clear off the soap; 4) lifting the belts out of the conveyors so the aprons surrounding the conveyors and the belt guides underneath can be cleaned; 5) repeating the high pressure hot water rinse to clear off any debris removed from the aprons or guides; 6) spraying a sanitizing solution on the conveyor.
Due to the stringent government regulations, this process is relatively standard in the food processing industry, although some variations may exist. The manual process does have several limitations, most obvious of which is amount of labor and time required for the process. The labor and time required to clean all of the conveyors in a single food processing plant will vary greatly depending on the number and length of the conveyors in the plant, but a typical plant is generally cleaned once per day.
In accordance with the objects listed above, the present invention is an automated conveyor cleaning system that performs most of the conventional conveyor cleaning steps without significant user intervention. The system involves outfitting the food processing plant with centralized high-pressure pumps, a chemical integration platform (xe2x80x9cCIPxe2x80x9d), and a plurality of strategically placed nozzle spray bars. The high-pressure pump allows for the rinse cycles to be performed at pressures higher than those used with a manual system.
The steps of the present invention are similar to those outlined above for a conventional system. The belts are first subjected to a high-pressure hot water rinse sent through the spray bars and nozzles by the central pumps. The same spray bars and nozzles are then used to coat the belts with detergent foam, after which the rinsing step is repeated. At this step the automated portion of the system pauses, so that the belts can be lifted out for cleaning underneath the belts and the conveyor aprons that surround the belts. To further aid the system, special lifters are used with certain types of conveyor belts to lift the belts out of the conveyor.
Once the side aprons are cleaned and the belts are returned to their operating location, the automated process continues with a high-pressure rerinsing to remove any debris left during the cleaning of the aprons or other manual cleaning. The spray bars then coat the belt with a low-pressure spray of sanitizing solution, which Is allowed to dry In place. Preferably the spray bars are then purged with pressurized air to remove any excess sanitizer in the spray bars.
Programmable logic controllers (xe2x80x9cPLCsxe2x80x9d) are used with the CIP, with the inlet valves of the spray bars, and with the high-pressure pumps. The conveyors (that have some common properties) are grouped together and each such group is controlled by a PLC. For each plant there could be many such groups called zones. The PLCs are all networked, possibly by a proprietary fiber optic system or wireless Ethernet and are in turn networked with a supervisory control system (typically run on an NT PC). This allows for logging of the various parameters used for cleaning (i.e. temperatures, pressure, time) and the amount of water or chemicals used.
The system can also easily change the dilution rate for the chemicals (stored in bulk) at the CIP. The CIP will typically have three bulk chemicals connected thereto: an industrial soap, and two types of sanitizers (the sanitizers are alternated based on the bacteria type and its resistance to the sanitizer), and is capable of supplying the diluted chemicals to the entire plant. The operation of the high-pressure pumps is preferably driven, by variable frequency drives (xe2x80x9cVFDxe2x80x9d) and controlled by one of the PLCs mentioned above.